@maxperhour To be on the safe side I would also try very short, 3 feet, Ethernet cable with Main Deco. Preferably one you had for a long time and if it is Cat5E - that would be the best option. In...

@NasseAlmojel You can have 300Mbps on Main Deco with M4, S4, S7 and any other WiFi5 Deco that has gigabit Ethernet ports. They all do, it is E4 that has 100Mbps ports. So, the very short answer: Yes.

@maxperhour Yes, but "hardware" could mean not just Main Deco but also Ethernet wiring and your ISP router. You said you tested it all, and I have no reasons not to believe you, but still the issue...

You said your Internet link is 300Mbps. This is the maximum you could get on WiFi inside your place, no matter what Main Deco you get. If you upgrade your ISP provided Internet link to, say, 500Mbps...

maxperhour wrote @Alexandre. So I placed the Decos into AP mode, and while the lights flashed red the app showed them working, in AP mode and could connect fine. Ran a speedtest via ethernet and...

@NasseAlmojel Yes, you can, but make sure you have the right expectations from that upgrade. You Main Deco will deliver up to 300Mbps on WiFi, your Satellite Decos will deliver probably not more than...